I could see it being a bit of both. Lyrics are often inspired by something and describing something else. In this case, someone stalking a former lover could be seen as “going full 1984’s Big Brother” on them… and it makes sense with the whole romantic mood that the song has: the stalker sees themself as romantic and sings it that way, but when you look closer you realise it’s actually very creepy.
I could see it being a bit of both. Lyrics are often inspired by something and describing something else. In this case, someone stalking a former lover could be seen as “going full 1984’s Big Brother” on them… and it makes sense with the whole romantic mood that the song has: the stalker sees themself as romantic and sings it that way, but when you look closer you realise it’s actually very creepy.